My mom's 2002 SL2 with 57,000 miles has had the service engine soon light on for a couple of days. The folks at Checher hooked it up to the computer and said that it was a misfire in cylinder1. The car barely would run. The guy at Checker said that it could need new plugs and wires. The plugs were changed at 30,000 miles with Bosh. My dad put new Bosh plugs and wires and diconnected the negative battery cable to reset the computer. The car seems fine now. My dad said that there was oil in 3 of the cylinders, what does all of this mean. Do we have a cylinder dying. By the way the car burns no oil and it is changed every 3,000. Any help is very much appreciated.

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Disconnecting the battery will not reset the computer. It does reset the SES light for SOME codes, but not all. If you need the SES light reset, the best way to do that is with a scanner/reader that's equipped to do so.

How did you discover "oil in the cylinders"? Was there raw oil in the combustion chambers? Raw oil on the spark plugs? Burned oil on the spark plugs?

Are the new spark plugs platinum? If so, replace them with coppers, preferably NGKs. These cars' "waste spark" system does not run properly on conventional platinum plugs.

BTW, generally, when you have a shop obtain the codes associated with the SES light, it's best to get the codes themselves, rather than their interpretation or description. In this case, it's pretty straightforward, but many code descriptions/interpretations do not actually reflect what has to be checked/repaired.

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I meant to say that three of the spark plugs had oil in them, not the cylinders. There was not a lot of oil on the plugs but some. Does anyone know what this could be?

Again, raw or burned oil?

If raw, it's most likely your cam cover gasket (specifically, the o-rings around the spark plug cavity holes) leaking. Easy fix; visit our How-To Library and search on "cam cover gasket". Your car has a nylon cam cover, which uses a rubber gasket set. The only places you need to use RTV are the two points where the timing cover meets the cylinder head.

If it's burned oil, well, there are several possible sources. We'll cross that bridge when (if) we come to it.

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The oil was raw I believe. Could the oil have caused the misfire? The plugs were not charred and were in very good shape.

Yes, very much so. It's not affecting the plugs themselves, but the wires. The only reason you see it on the plugs is that, at the moment you remove the plugs, the pooled oil drains down on them. While the plugs are installed, none of the leaking oil is getting on the plugs themselves.

Oil is leaking from the o-ring spark plug seals, which are part of the cam cover gasket set. Oil pools in the spark plug wells, and soaks the spark plug wires. The oil acts as a conductor, scavenging spark energy that should go to the spark plug tip and grounding it through the head. Replacing the spark plug wires and letting the pooled oil drain into the chambers has temporarily fixed the problem, but in short time, more oil will pool and you'll be back where you were. Replace the cam cover gasket set, and if there's any new oil pooled in the spark plug wells, sop it up with paper towels. That should get you out of the woods.

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Well the sevice engine light is on again. I guess that we need to take the car in to the dealer. Why would the oil that is raw in three of the cylinders cause only one of the cylinders to misfire. The car is not missing yet but the light is back on. What else could be causing this misfire other that a leaking cam cover gasket set? By the way how much is it to replace a cam cover gasket at a Saturn retailer? Is this something that I could do for my mom?

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Well the sevice engine light is on again. I guess that we need to take the car in to the dealer. Why would the oil that is raw in three of the cylinders cause only one of the cylinders to misfire. The car is not missing yet but the light is back on. What else could be causing this misfire other that a leaking cam cover gasket set? By the way how much is it to replace a cam cover gasket at a Saturn retailer? Is this something that I could do for my mom?

It could be that Autozone, or wherever you took it, didn't read all the codes; maybe they just grabbed the first one that came up, and pulled the plug. You may still have misfires on the others. The misfires could be infrequent enough that you don't feel it when driving it, but it still sets the SES light. Or the SES may be for a whole 'nother reason.

The cam cover gasket is a pretty easy DIY, for your model year. And AFAIK, they charge quite a bit labor for it. There are instructions in our How-To Library. Your mom's car has the later (Gen 3, in this case) composite cam cover, which uses a rubber gasket set (including the o-rings for the spark plug holes). You need to put a little bit of RTV silicone on the two points where the timing cover mates with the head, but not anywhere else. So if you see any instructions about using RTV to create the gasket itself, don't follow them; that's for the earlier, aluminum cover.

You should also look at the spark plug wires. If the oil pooling has been really bad, it could have saturated the wires to the point where they're no longer able to conduct the spark energy entirely to the plug. If you don't know how many miles are on the existing spark plug wires, it'd be good measure to replace them anyway. Another very simple job; I think you use the same size wrench as you do for the cam cover gasket.

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